summaryrefslogtreecommitdiff
path: root/src/thread/pthread_create.c
blob: adef510c5298c810d09b14e8666cd0359ae8c2d3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
#include "pthread_impl.h"
#include "stdio_impl.h"

static void dummy_0()
{
}
weak_alias(dummy_0, __synccall_lock);
weak_alias(dummy_0, __synccall_unlock);
weak_alias(dummy_0, __pthread_tsd_run_dtors);

#ifdef __pthread_unwind_next
#undef __pthread_unwind_next
#define __pthread_unwind_next __pthread_unwind_next_3
#endif

void __pthread_unwind_next(struct __ptcb *cb)
{
	pthread_t self = pthread_self();
	int n;

	if (cb->__next) {
		self->cancelbuf = cb->__next->__next;
		longjmp((void *)cb->__next->__jb, 1);
	}

	__pthread_tsd_run_dtors();

	__lock(&self->exitlock);

	/* Mark this thread dead before decrementing count */
	__lock(&self->killlock);
	self->dead = 1;
	a_store(&self->killlock, 0);

	do n = libc.threads_minus_1;
	while (n && a_cas(&libc.threads_minus_1, n, n-1)!=n);
	if (!n) exit(0);

	if (self->detached && self->map_base) {
		__syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1},0,8);
		__unmapself(self->map_base, self->map_size);
	}

	__syscall(SYS_exit, 0);
}

static int start(void *p)
{
	struct pthread *self = p;
	if (self->unblock_cancel)
		__syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8);
	pthread_exit(self->start(self->start_arg));
	return 0;
}

int __uniclone(void *, int (*)(), void *);

#define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)

/* pthread_key_create.c overrides this */
static const size_t dummy = 0;
weak_alias(dummy, __pthread_tsd_size);

static FILE *const dummy_file = 0;
weak_alias(dummy_file, __stdin_used);
weak_alias(dummy_file, __stdout_used);
weak_alias(dummy_file, __stderr_used);

static void init_file_lock(FILE *f)
{
	if (f && f->lock<0) f->lock = 0;
}

int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(void *), void *arg)
{
	int ret;
	size_t size = DEFAULT_STACK_SIZE + DEFAULT_GUARD_SIZE;
	size_t guard = DEFAULT_GUARD_SIZE;
	struct pthread *self = pthread_self(), *new;
	unsigned char *map, *stack, *tsd;

	if (!self) return ENOSYS;
	if (!libc.threaded) {
		for (FILE *f=libc.ofl_head; f; f=f->next)
			init_file_lock(f);
		init_file_lock(__stdin_used);
		init_file_lock(__stdout_used);
		init_file_lock(__stderr_used);
		__syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8);
		libc.threaded = 1;
	}

	if (attr) {
		guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
		size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
	}
	size += __pthread_tsd_size;
	map = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
	if (!map) return EAGAIN;
	if (guard) mprotect(map, guard, PROT_NONE);

	tsd = map + size - __pthread_tsd_size;
	new = (void *)(tsd - sizeof *new - PAGE_SIZE%sizeof *new);
	new->map_base = map;
	new->map_size = size;
	new->pid = self->pid;
	new->errno_ptr = &new->errno_val;
	new->start = entry;
	new->start_arg = arg;
	new->self = new;
	new->tsd = (void *)tsd;
	if (attr) new->detached = attr->_a_detach;
	new->unblock_cancel = self->cancel;
	memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc);
	new->tlsdesc[1] = (uintptr_t)new;
	stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15);

	__synccall_lock();

	a_inc(&libc.threads_minus_1);
	ret = __uniclone(stack, start, new);

	__synccall_unlock();

	if (ret < 0) {
		a_dec(&libc.threads_minus_1);
		munmap(map, size);
		return EAGAIN;
	}
	*res = new;
	return 0;
}

void pthread_exit(void *result)
{
	struct pthread *self = pthread_self();
	struct __ptcb cb = { .__next = self->cancelbuf };
	self->result = result;
	__pthread_unwind_next(&cb);
}